Description: (Taken directly from the application) This proposed Core Laboratory is a consolidation of two Core laboratories, the first, Hormone/Metabolite, has been in operation since the New York Obesity Research Center (NYORC) was first funded in 1980; the second, Mass Spectroscopy, was added as a Core Laboratory in 1990. Both have been used very heavily, probably because it has been extraordinarily helpful for investigators not to have to set up methods for analyses that are more efficiently done by this Core, thereby allowing for greater productivity at lesser cost to the Users. They have been consolidated under one core with Dr. Pi-Sunyer as Director. The rationale for this is that the Mass Spectroscopy Sub-Core is at the University of Vermont and there is need for a communication center and sample-processing center for Users in New York. The User requests for service for the two Sub-Cores will come to Dr. Pi-Sunyer, who in consultation with Dr. Mathews, will prioritize use of each of the Sub-Cores and arrange for sample processing, analysis, reporting, and record keeping. Dr. Pi-Sunyer will direct the Hormone/Metabolite Sub-Core and Dr. Mathews the Mass Spectroscopy Sub-Core.